Stock L92 Head Flow Data
Originally Posted by NO-OPTION-2002
They're not.
L92 = #10214664 int. #12569167 exh. 1.7:1 ratio
LS7 = #12579615 int. #12579617 exh. 1.8:1 ratio
Hope this help with some of the confusion.
L92 = #10214664 int. #12569167 exh. 1.7:1 ratio
LS7 = #12579615 int. #12579617 exh. 1.8:1 ratio
Hope this help with some of the confusion.
what are the odds of someone posting up a pic of the GM diagram, and a list of all the parts needed for the swap.....?
btw, im going to stick with the 1.7 ratio if i can... 1.8s are nice, but the agressive lobes i will eventually put in there wernt designed to move the valve that fast.. they were made for the 1.7s.. and pushing that hard. lol.
Originally Posted by MrDude_1
could you elaborate?
why wont the L92 valvetrain work with L92 heads on a diffrent shortblock??
why wont the L92 valvetrain work with L92 heads on a diffrent shortblock??
And FWIW, if shimmed correctly there's not any adverse affects on your springs going from 1.7 to 1.8 rocker ratio.
Nate
Originally Posted by Nate_Taufer
The L-92 rockers and LS7 rockers are pretty much identical except for the 1.8 versus 1.7 rocker ratio. They're both offset rockers for the huge intake port. The L92 valvetrain will work just fine. I just figure if Im getting the same priced rockers I might as well splurge for a higher ratio at the time.
And FWIW, if shimmed correctly there's not any adverse affects on your springs going from 1.7 to 1.8 rocker ratio.
Nate
And FWIW, if shimmed correctly there's not any adverse affects on your springs going from 1.7 to 1.8 rocker ratio.
Nate
but thats off the subject... getting back on track, whos going to be the first one to have this on a running performance app??? i know im not.. its a side project with 2 other car projects going on.. so it'll be awhile.. lol.
Originally Posted by Richard@WCCH
I just finished flow testing a new stock L92 head. All I can says is…….WOW! What a nice part.
Valve dimensions:
Intake = 2.160” X 4.870” X .314”(8mm)
Exhaust = 1.590” X 4.920” X .314”(8mm)
Seat/throat diameters:
Intake = 1.870”
Exhaust = 1.355”
Richard
Valve dimensions:
Intake = 2.160” X 4.870” X .314”(8mm)
Exhaust = 1.590” X 4.920” X .314”(8mm)
Seat/throat diameters:
Intake = 1.870”
Exhaust = 1.355”
Richard
Nate
TECH Regular
Joined: Nov 2005
Posts: 459
Likes: 0
From: Arlington, TN
You could probably use either Comp Cam's Pro Magnum Roller Rockers or Crane Cam's Gold Series (as neither are shaft mounted).
Basicly the 1.7 or 1.8 sets should work with a new guide plate (due to the offset valves). The studs, locks, and rockers would be used though.... just new guide plates.
Basicly the 1.7 or 1.8 sets should work with a new guide plate (due to the offset valves). The studs, locks, and rockers would be used though.... just new guide plates.
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Originally Posted by Bring the Noise
You could probably use either Comp Cam's Pro Magnum Roller Rockers or Crane Cam's Gold Series (as neither are shaft mounted).
Basicly the 1.7 or 1.8 sets should work with a new guide plate (due to the offset valves). The studs, locks, and rockers would be used though.... just new guide plates.
Basicly the 1.7 or 1.8 sets should work with a new guide plate (due to the offset valves). The studs, locks, and rockers would be used though.... just new guide plates.
Nate
these are an awesome set of heads, especially for stock!!
anyone else confused about the 260cc runner volume?? why is it so large? aren't these on about ~370cid stock? considering its going in a 5000lb SUV wouldn't you want smaller runners to help with tq?
anyone else confused about the 260cc runner volume?? why is it so large? aren't these on about ~370cid stock? considering its going in a 5000lb SUV wouldn't you want smaller runners to help with tq?
Originally Posted by 383ss
these are an awesome set of heads, especially for stock!!
anyone else confused about the 260cc runner volume?? why is it so large? aren't these on about ~370cid stock? considering its going in a 5000lb SUV wouldn't you want smaller runners to help with tq?
anyone else confused about the 260cc runner volume?? why is it so large? aren't these on about ~370cid stock? considering its going in a 5000lb SUV wouldn't you want smaller runners to help with tq?
because the goal isnt high velocity..the goal is just "let as much air as possible into the motor, as easily as possible"..
seriously though, just because the intake port is huge, doesnt mean it has to suck down low.. im sure ALOT of R&D has gone into the design of this port.
Originally Posted by ChucksZ06
Does anyone have part numbers for the valves? will ls1 rockers work on the exhausts? I know the intakes are the offset rockers...part numbers for rockers? Thanks.
Originally Posted by MrDude_1
because the goal isnt high velocity..the goal is just "let as much air as possible into the motor, as easily as possible"..
seriously though, just because the intake port is huge, doesnt mean it has to suck down low.. im sure ALOT of R&D has gone into the design of this port.
seriously though, just because the intake port is huge, doesnt mean it has to suck down low.. im sure ALOT of R&D has gone into the design of this port.
Originally Posted by 383ss
hmm. then why is it beat into our heads by AFR and others that small well flowing chambers are the way to go for best hp/tq
Originally Posted by Greg Fell
Velocity is great. But, the bottom line is, you still need air. In other words, if you only had wicked port velocity, but only 150 cfm, you'd make great tq and such, but a 500 cfm head that has lower velocity would crush it up top.
hell, ETP recommends 240cc heads for 408's unless they are race motors then the 255cc head. AFR's 205 is enough to feed 500rwhp. 260 to 205 is a HUGE difference, IMO.
Originally Posted by 383ss
I understand that, but for a stock motor you need that kind of flow and 260cc runners?? I don't get it. I serioulsy doubt GM is looking for killer 'up top' numbers for an escalade.
hell, ETP recommends 240cc heads for 408's unless they are race motors then the 255cc head. AFR's 205 is enough to feed 500rwhp. 260 to 205 is a HUGE difference, IMO.
hell, ETP recommends 240cc heads for 408's unless they are race motors then the 255cc head. AFR's 205 is enough to feed 500rwhp. 260 to 205 is a HUGE difference, IMO.
Originally Posted by 383ss
hmm. then why is it beat into our heads by AFR and others that small well flowing chambers are the way to go for best hp/tq
think about this:
for decades guys have been hogging out intake runners... with a large cam, large displacement, you make large peak numbers.. great for racing.
but on the street, you end up with the usual drives shitty drag car. the "area under the curve" drops waaay down when you're not using that big port.
so AFR and other cyl head guys work their best to make a large flowing head, that also has enough velocity to work on lesser flowing motors... like everything, its a compromise.. and for 90% of the market, it works better..
Originally Posted by 383ss
I understand that, but for a stock motor you need that kind of flow and 260cc runners?? I don't get it. I serioulsy doubt GM is looking for killer 'up top' numbers for an escalade.
hell, ETP recommends 240cc heads for 408's unless they are race motors then the 255cc head. AFR's 205 is enough to feed 500rwhp. 260 to 205 is a HUGE difference, IMO.
hell, ETP recommends 240cc heads for 408's unless they are race motors then the 255cc head. AFR's 205 is enough to feed 500rwhp. 260 to 205 is a HUGE difference, IMO.
think about the millions in R&D work GM put into the LS7 head program.. they're using what they learned there on their massed produced cars.. the less intake restriction, the better. and with this new cyl deactivation routine, these engines will be seeing double the airflow in each cyl. GM figured out a way to make these heads flow alot and work well thru alot of R&D.
companies like ETP and AFR are somewhat limited in that they have to remain close to "stock ports".. otherwise, headers, intakes, ect would come into play, and you'd end up spending waaay too much for those heads to work for you. so even if they know widening the port, doing xyz makes the head flow better, they cant do it. GM did not have this limitation.
really, these heads probably arnt going to be best for everyone.. but for the engine im trying to build, i believe it will work great. im also not expecting an ideal street car. lol.